1. Field of the Invention
The present invention relates to a parking brake system for use with an automotive transmission and more particularly to an electrically operated parking sprag for operatively engaging a parking gear.
2. Background and Summary of the Invention
The members of the consuming public who have preferred automobiles with automatic transmissions have become accustomed to a standard shift lever system which includes a PRNDL shift arrangement. In this shift arrangement, when the shift lever is shifted to the "P" position, the automatic transmission is automatically shifted to a park condition. Recently, there has been research and development in the area of providing automated manual-type transmission systems. The automated manual transmission systems have the simplicity and convenience of automatic transmission while maintaining the higher efficiency of a manual transmission. However, it is typical that a manual transmission does not include a park feature. Instead, manual transmission vehicles are typically provided with a parking brake which is activated by the driver of the vehicle. Typically, parking brake systems for vehicles having a manual transmission provide a dual function as an emergency brake which frictionally engages the vehicle wheels to inhibit rotation. In addition, manual transmissions are often placed in gear by the operator after the vehicle engine is turned off in order to provide an effective brake for the vehicle in a parked condition.
However, in converting a manual transmission to an automated manual transmission, it is desirable to provide a shift lever which simulates that of a standard automatic transmission including a parking "P" position. Accordingly, the present invention provides an electrically operated parking sprag for engaging a parking gear mounted on an output shaft of a transmission which is responsive to a shift lever being moved to the park position.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.